AP Computer Science

The 1996 Reading Process“how the papers were marked”

by Dave Slemon, slemon@interware.net

Clemson UniversitySouth Carolina, June 1996

All of the 1996 computer papers were marked at Clemson.

11,000 Computer papers were read by 85 readers.

6200 A - exams 4800 AB - exams The reading team

consists of:– 1 Chief Reader

– 2 Exam Leaders

– 12 Question Leaders

– 70 Readers

Address from the Chief Reader the Chief Reader co-ordinates

11-12 question leaders, and they– create and test all of the rubrics

for each question

– discuss each question with all 85 readers

– the creation of training packs designed to help teach readers to mark consistently.

the Chief Reader alone

– oversees all aspects of the reading

– decides who gets 5’s, 4’s, 3’s, etc.. one week later in Princeton.

1 question is read per room Each room is responsible for

marking one entire question, (eg., all 6000 of the number 3’s on the A exam).

The ladies in the hall shuttle the papers from room to room.

Black bandages cover previous scores given by other readers on other questions.

The rubric & scoring sheet

The rubric is the marking scheme. The readers never put anymarks into the student’s booklet; they use their own scoring sheet.

The Question Leaders

One is a college professor and the other is a high school teacher.

They teach the 12 other readers how to grade using the carefully prepared rubric.

Each reader trains on 250 papers before marking one single real paper.

Each question has 2 Question Leaders who sit at the front of the room.

Readers

Each reader has one partner.

25 papers make up 1 pack. Each paper is read

separately by each partner. Each Reader scores the

paper on their persona-lized scoring sheet.

Charts on the wall serve as reminders.

The 12 readers in this room are marking the 1995 sequence question.

Reading the same question

Question 4 of the 1995 A paper is being marked in this room.

Documentation is not marked.

Compiler-catching errors are not penalized.

Obobs (off by one bug) lose marks.

Back reading

Back reading is usually done by the Question Leaders. The Leaderslook for discrepencies between the two scoring sheets. They resolveall discrepencies by conferring with the two Readers who disagreed.

Things that really matter

getting the idea point. accurate loop

counting. testing all of your

cases. check boundary

conditions carefully. setting the function

value correctly.

Things that don’t matter

semicolons documentation choice of variable

names indenting = instead of := compiler catching

syntax errors

Common errors Improper addressing

struct CARD {int partNum;apstring description;int quantity;double price;

};

CARD index;cin >> partNum; should be:

cin >> index.partNum;

Some patterns over the years

Computer Science AB Exam– My students rarely finish the 40 multiple choice

questions; finishing the ones you do correctly is more important!

– Usually there are 4 long answer questions, with some of the questions having parts (a) - (d).

1. A case study question, e.g. BigInt2. A string or a 2-D Array or a File.3. A linked list question.4. A tree question.

Interesting Observations‘...but no guarantees’

Computer Science A Exam– My students rarely finish the 40 multiple choice– There are usually 4 long answer questions.

1. A 2-D array, with nested-looping.2. A string or file question.3. A case study question e.g. BigInt4. A record-based question using struct.

The Scoring Sheet

1998 1 111 1 1 1 -1 82

+1 idea+1 init+1 accumulation+1 correct

4/4

+1 idea+1 init+0 accumulation (function name used as local variable)

+1 correct-0.5 usage (i/o)

3/4

+1 idea+1 init+1 accumulation+1 correct-0.5 usage ( )-0.5 i/o errors

3/4

+1 idea+1 init+0 accumulation+1 correct

3/4count

+1 idea+1 init+1 accumulation+0 correct

3/4n